1. Technical Field
The present invention relates to a polarization element, a projector, a liquid crystal device, an electronic apparatus, and a method of manufacturing the polarization element.
2. Related Art
There is known a wire grid polarization element as a type of polarization element (e.g., Japanese Patent No. 4,411,202 (Document 1), JP-A-10-73722 (Document 2)). The wire grid polarization element is provided with a configuration in which a transparent substrate is lined with a grid made of metal at a pitch shorter than the wavelength of a light used therein. The wire grid polarization element can be composed only of inorganic substances, and therefore, has remarkably small deterioration caused by light irradiation compared with a polarization plate made of an organic substance, and attracts the attention as an effective device in the liquid crystal projector field increasing in brightness.
The wire grid polarization element is provided with an excellent heat resistant property, and is required to have further high-temperature reliability due to the increase in brightness of the liquid crystal projector in recent years.
In Document 1, aminophosphonate is formed on a surface of the wire grid polarization element, thereby achieving protection of the metal grid. However, since the aminophosphonate, which is an organic molecule, is decomposed in a purpose of being heated to 200° C. or higher, it is not achievable to assure sufficient reliability.
Incidentally, in Document 2, a surface of the metal grid (metal thin wire) on a substrate is oxidized by a heat treatment to thereby improve the environment resistance. However, since it is required to heat the substrate to 500° C. or higher for the oxidation process, breakage or deformation of the substrate is caused in some cases. Further, in some cases, the metal grid itself is damaged by the heat expansion, and thus the dimensions such as the height or the width of the metal grid determining the optical characteristics may change.